Idiopathic pneumonia syndrome (IPS) refers to diffuse lung injury which can occur following haematopeotic stem cell transplantation where neither an infectious nor non-infectious etiology can be found.
The incidence of IPS is thought to be around 12% following haematopoetic stem cell transplantation.
Clinical presentation can vary from being asymptomatic to full blown acute respiratory distress syndrome. Its median onset time is around 40-50 days following transplantation, but there is an early peak in the first 14 days, followed by a lower but consistent incidence up to around 80-100 days.
Its etiology is thought to be multifactorial inclusive of chemoradiotherapeutic insults and graft versus host disease 4. There are two main histopathological patterns
- interstitial pneumonitis
- diffuse alveolar damage
Plain radiograph / CT
- would typically show diffuse airspace and/or intestinal infiltrative opacification 4
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